Recovery of soluble products from solid carbonizable substances



Patented Sept. 8, 1931:

V UNITED STATES PATENT OFF-ICE I JOSEF .mnnnx AND OTTO Gonna, orLUnwmsHarEmoN-mE-mzmn, 6mm, as- SIGNOBS TO 1. G. rannnmnnusrnrn.AKTIENGESELLSCHAFT, or raamzlonr-ox- THE-MAIN, GERMANY, A CORPORATIONOF GERMANY BECOVERY OF SOLUBLE PRODUCTS FROM SOLID CARBONIZABLESUBSTANCES y lo Drawing. Application filed March 15, 1928, Serial No.262,041, and in Germany Iarch 18, 1527.

This invention relates .to the production of soluble products fromcarbonizable substances. By soluble products wherever this term isemployed in the present application, are understood those productspresent in carbonizable substances or which are formed therein by heattreatment, which when isolated therefrom are either semisolid or solidand are wholly or in part fusible and as a rule have a blackish color,and

which are soluble in liquid organic solvents. The said products have acontent in hydrogen a which is about twice that of the carbonizablesubstances from which they have been extracted and they only containabout half the amount of oxygen. 7

It has already been proposed to improve the yield of soluble productsobtained by extraction from coal with distillable liquid organicsolvents either by heating the coal, under pressure, in the presence orabsence of a distillable liquid organic solvent, and then effecting theextraction of the said soluble products by lixiviating with a largeramountof the said solvent, or, by heating the coal by itself withoutpressure, and then extract ing as aforesaid, or, by heating underpressure with a distillable liquid organic solvent, after preheatingwithout pressure, and then extracting. According to all known means,however, the increased yield, if any, is not very considerable.

We have now found that an unexpectedly high yield of the said solubleproducts may be obtained by extraction from carbonizable substances suchas coal, or like carbonaceous materials, with distillable liquid organicsolvents, if the said carbonizable substances are first heated bythemselves in a closed vessel under pressure, and are then treated byextraction with an adequate amount of one of the said solvents, also ina closed vessel, at an elevated temperature and under pressure but theconditions of working must be so chosen in both stages of the process,when gases or vapours capable of reacting with the materials undertreatment are employed, that no substantial reaction with the said gasestakes place. It should be understood that the expression carbonizablesubstances when employed in connection with the present invention doesnot include brown coal containing considerable amounts of moisture. Inboth stages the pressure is spontaneously set up by the heating, and itmay be increased by the addition of non-oxidizing gases or vapors, whichare equivalents for the purposes of the present invention and whichunder the conditions of. working do not react to a substantial extentwith the caramount and kind of solvent, in order to obtain a maximumyield of soluble products in any given instance, must be adapted to suitthe type of coal and solvent. When preheating brown-coal for example,temperatures between 200 and 400 C. are suitable. \Vhen preheatingthecoal, it is preferable to employ temperatures and pressures which do notcause the coal to cake. After heating under pressure, the coal may havea considerably modified appearance, but it is nev erthelesssubstantially still in a firm condition. The coal is then, preferablywhile still hot, treated with a solvent, or mixture of solvents, in aclosed vessel and at anelevated temperature, additional pressures beingapplied. as required, themass being preferably kept in motion orstirred. It may sometimes be advantageous to extract twice, or a greatornumber of times, with the same solvent, or differentsolvents. Suitablesolvents according to the present invention comprise, for example,hydrocarbons such as benzene and its derivatives, hydrogenatednaphthalenes, alcohols, ketones, petroleum, mineral oils, tar oils andthe like. Cyclic alcohols and ketones, such as cyclohexanol andcyclowhich may extend-to several hours,

hexanone, and the like may be mentioned as being particularly suitable.

The process herein described may be applied to coals, or carbonaceous orcarbonizable substances of any kind as for example brown-coal, peat,humus coal, pit coal, wood, oil shale, carbonaceous shale and the like.

The following examples will further illustrate the nature of the saidinvention, but the invention is not limited thereto.

Ewample 1 A pressure-tight vessel is about half filled with dry browncoal (lignite). After displacing the air from the said vessel by meansof nitrogen the material to be treatedis heated to a. temperature ofabout 300 C. whereby a pressure of about 150 atmospheres or nrorc is setup. If desired a non-oxidizing gas, such for example as nitrogen may bepressed into the said pressure-tight vessel prior to heating. In thiscase the pressure attained by heating is still higher. After heating forabout l0'hours, the vessel is allowed to cool down for about 3 to 6hours, depending on the amount of the charge and, after releasing thepressure, about double the amount of distillable liquid organic solvent,such as benzene, is introduced to the pretreated lignite. After closingdown the vessel, the materials are again heated to a temperature ofabout 300 C., if desired, after pressing in, for example 30 atmospheresof nitrogen. 'After heating for about 4 to 10 hours the vessel is againallowed to cool down for about 3 to 6 hours and is relieved of pressureand is emptied. After filtering, centrifuging or similarly treatingtheproduct thus obtained, whereby the solid materials are separated fromthe liquid constituents, the solid residue is washed with furtherquantities of fresh solvent or is further sub jected to extraction bymeans of a solvent without the application of pressure. The

, solvent may be removed from the products which have been extractedfrom the lignite by means of simple distillation or vacuum distillationor steam distillation.

Example 2 Dry brown-coal from the mid-German field, from which 1.7 percent of bitumen can be extracted with benzene' in a Soxhlet apparatus,is heated at 300 C. for 10 hours in an autoclave, during which treatmenta pressure of about 100 atmospheres is produced, and a loss in weight ofabout 14 per cent occurs. The material which has been thus pretreated issubjected to extraction with benzene for 10 hours at 300 C. in a closedvessel a pr ure of about 100 atmospheres being thus set 11 A yield ofover 60 per cent of soluble products with reference to the coalsubstance treated, is thus obtained.

The soluble products obtained according to the foregoing example may besubjected either alone or in association solvent I or the undissolvedresidue to further treatment, such as a crackin rocess in the presenceof activated aluminium and hydrogen chlorid, or to destructivehydrogenation. After separation of the insoluble portion and thesolvent, the said products may also be separated, by the aid of suitablesolvents, into resins, waxes and other substances, as for example, byfirst treating the product with ether to extract the resinousconstituents, and then extracting the Wax-likeconstituents from theresidue by treating with hexane or the like. Theconstituents mayafterwards be used as such or subjected to further treatment.

What we claim is:

1. A process for the production of products which are soluble in organicli uids from solid carbonizable substances w ich' comprises heating thesaid carbonizable substances under a pressure of at least 2 atmospheresat a temperature of at least100 C. but below the point at which the saidcarbonizable substances cake, and then treating the products thusobtained b extraction with an adequate amount of a iquid distillableorganic solvent at an elevated temperature and under a pressure of morethan 2 atmospheres, the conditions of working in both stages of theprocess being so chosen that, when gases or vapours capable of reactingwith the materials under treatment are employed, no substantial reactionwith the said gases takes place.

2. A process for the production of products which are soluble in organicli uids from solid carbonizable substances w ich comprises heating thesaid carbonizable substances to temperatures of between 100 and 600 C.under a ressure of more than 2 atmospheres and t en treating theproducts,

while still hot, by extraction with an adequate amount of a distillableliquid organic solvent at a pressure of more than 2 atmospheres, theconditions of working being so chosen in both stages of the process,when gases or vapours capable of reacting wi h the materials undertreatment are employe that no substantial reaction with the said gasestakes lace.

3. process for the production of products which are soluble in organicliquids from solid carbonizable substances which comprises heating thesaid carbonizable substances together with a gas which under theconditions of working does not react to a substantial extent withthecarbonizable matter to temperatures between 100 and 600 C. under apressure of more than 2 atmospheres and then treating the product, whilestill hot, by extraction with an adequate amount of a distillable liquidorganic solvent at a pressure of more than 2 atmospheres, the conditionsof worldng being so chosen in the said i i takes place, and thentreating the product,

while still hot, by extraction with a distillable liquid organic solventand a gas which under the conditions of working does not react with thecarbonizable material at a pressure of more than 2 atmospheres.

5. A process for the production of products which are soluble in organicliquids from solid carbonizable substances which comprises heating thesaid carbonizable substances, together with a gas, which, under theconditions of working, does not react to a substantial extent with thecarbonizable material, to temperatures of between 100 and 600 C. under apressure of more than 2 atmospheres and then treating the product, whilestill hot, by extraction with an adequate amount of a distillable liquidorganic solvent together with a gas which under the conditions ofworking does not react to a sub stautial extent with a carbonizablematerial, at a pressure of more than 2 atmospheres.

6. A process for the production ofproducts which are soluble in organicliquids from solid carbonizable substances which comprises heating thesaid carbonizable substancesunder a pressure of more than 2 atmospheresand at a temperature of between 100 and 600 C. and then treating theproduct by extraction with an adequate amount of a distillable liquidorganic solvent at an elevated temperature and at a pressure of morethan 2 atmospheres, the conditions of working being so chosen in bothstages of the process, when gases or vapours capable of reacting withthe materials under treatment are employed, that no substantial reactionwith the said. gases takes place, and subjecting the resulting productsto a crackin operation.

7. A process for tl ie production of products which are soluble inorganic liquids from solid carbonizable substances which com prisesheating dry brown coal to temperatures of between 200 and 400 C. under apressure of more than 2 atmospheres which is not so high as to cause thecoal to cake, and then treating the product, while still hot, byextraction with an adequate amount of a distillable liquid organicsolvent at a pressure of more than 2 atmospheres, the conditions ofworking being so chosen in both stages of the process, when gases orvapours capable of reacting with the materials under treatment areemployed, that no substantial reaction with the said gases takes place.

8. A process for the production of products which are soluble in organicliquids from solid carbonizable substances which comprises heating drybrown coal to about 300 C. for hours at a pressure of about 100atmospheres and then subjecting the product to extraction by heatingwith an adequate amount of benzene for further 10 hours at about 300 C.under a pressure of more than 2 atmospheres, the conditions of workingbeing so chosen in both stages of the process that, when gases orvapours capable of reacting with the materials under treatment areemployed, no substantial reaction with the said gases takes place.

9. A process for the production of products which are soluble in organicliquids from solid carbonizable substances which comprises heating thesaid carbonizable substances under pressure at a temperature of at least100 C. and below the point at which the said carbonizable substancescake and then treating the product thus obtained by extraction with atleast twice the amount of a liquid distillable organic solvent at anelevated temperature and at a pressure of more than 2 atmospheres, theconditions of working being so chosen in both stages of the processthat, when gases or vapours capable of reacting with the materials undertreatment are employed, no substantial reaction with the said gasestakes place.

In testimony whereof we have hereunto set our hands.

JOSEF J AN NEK. OTTO GOHRE.

